Let's talk about the teacher's work day.
Your link says it's 6 hours and 55 minutes, including lunch. So 6 hours and 25 minutes is a work day.
Plus there's 150 minutes a week (2 and a half hours, or 30 minutes per day) for training, professional development, teacher collaboration, parent engagement and other professional activities.
150 minutes for all of that is a joke, and if any teacher was actually following that rule (union or not) then you'd be hearing about it.
What are "other professional activities?
Students that need extra help?
Students that need to make up work/tests?
Grading homework/tests/quizzes
I have about 150 students. If I give a test, that's 150 tests to grade. If it takes me 1 minute to grade each test, then I've just blown that entire quota of "other professional activities"
But I still do my job.
I grade all those 150 tests. Then I grade the homework that I gave all those students. Then I write my lesson plans for the next classes and I write the next test. And I email/call parents. And I meet with parents. And I see students before/after school to answer their questions and have them make up their work and tests. And I answer emails from students that have questions about their homework.
I spend 6 hours and 25 minutes a day teaching. I spend plenty more time making sure students learn.
But at least I get summer vacation, right? Sure, it's just full of mandatory Professional Development (so I can keep my teacher license up to date) and lesson planning for the next year.
But hey, in New York you can make up to $105k! After 22 years AND earning a PhD (which you paid for with your own money ... and where did you find the time to get that degree?) Rent in NY is 3x rent where I live, but the max $105k isn't even 3x the starting salary of my school district.